1. Field of the Invention
The present invention relates to hydraulic tools and, more particularly, to a hydraulic tool with a multi-speed rapid ram advancement system.
2. Brief Description of Prior Developments
U.S. Pat. No. 4,339,942 discloses a hydraulically operated crimping tool. The tool has a hydraulic piston with a central recess that receives a member with a duct. A rear end of the member is screwed into the frame of the tool and is adapted to conduit oil into the central recess.
There is a desire to provide a hydraulic tool, such as a crimping tool or a cutting tool, which has a rapid ram advanced feature, but which can accommodate longer stroke lengths of the ram. Hydraulic tools, such as crimping tools and cutting tools, can comprise rotatable heads wherein the ram of the tool is adapted to rotate relative to the frame of the tool. With this type of rotatable head hydraulic tool, a conduit member such as described in U.S. Pat. No. 4,339,942 can cause problems because of the threaded engagement between the conduit member and the frame. This threaded engagement can loosen or become disconnected because of rotation of the rotatable head; transferred to the conduit member by friction between the ram and the conduit member. In addition, vibrations in a tool, such as a battery operated hydraulic tool, can also cause this threaded engagement to loosen or become disconnected. There is a desire to provide a tool which can accommodate longer stroke lengths of the ram, have a rotatable head and a conduit tube which extends into the ram, but with a system to prevent disconnection of the conduit tube from the frame which otherwise might occur with a threaded connection because of rotation of the head or vibrations in the tool. There is also a desire to provide a hydraulic tool with a conduit tube extending into a ram cavity wherein the conduit tube is easier to connect to a frame of the tool.